1. Field of the Invention
The invention relates to a method of obtaining a structure on a semiconductor wafer by etching through a low-k silicon based organic dielectric layer.
2. Description of the Related Art
In semiconductor plasma etching applications, a plasma etcher is usually used to transfer an organic mask pattern, such as a photoresist mask pattern, into a circuit and line pattern of a desired thin film and/or filmstack (conductors or dielectric insulators) on a Si wafer. This is achieved by etching away the films (and filmstacks) underneath the photoresist materials in the opened areas of the mask pattern. This etching reaction is initiated by the chemically active species and electrically charged particles (ions) generated by exciting an electric discharge in a reactant mixture contained in a vacuum enclosure, also referred to as a reactor chamber. Additionally, the ions are also accelerated towards the wafer materials through an electric field created between the gas mixture and the wafer materials, generating a directional removal of the etching materials along the direction of the ion trajectory in a manner referred to as anisotropic etching. At the finish of the etching sequence, the masking materials are removed by stripping it away, leaving in its place a replica of the lateral pattern of the original intended mask patterns.